Messier Marathon: Take a long run around the sky

Charles Messier (1730-1817) was a French comet hunter. While he did discover 13 comets, his more famous contribution to astronomy was a list he made of objects that were not comets.

In the small telescope that he had available, the only way to distinguish a comet from any other dim, fuzzy object was whether or not it moved in the sky from one night to the next. To avoid unnecessary observations, Messier recorded the locations of the stationary objects he found. Anything that was dim and fuzzy and did not move from night to night would make it onto his list.

The final list of 110 objects includes galaxies, diffuse nebulae, planetary nebulae, globular clusters and open clusters. The only thing they have in common is that they are, in fact, not comets. Many are faint naked-eye objects, and many more can be seen with binoculars. All can be seen with a small telescope, although some might be a challenge.

This month

The Messier objects are not distributed evenly around the sky. They are all visible in the Northern Hemisphere. And a bit by chance, in late March it is possible to observe all 110 objects on a single night. Finding all 110 in a single night is called a Messier Marathon. I wish you the best of luck if you are going to attempt that. With the waxing moon heading toward full, last week might have been a better week for an attempt.

In the meantime, here are a couple of easy Messier objects to find.

Object number 45 on Messierís list is the Pleiades, or Seven Sisters. This is an open cluster easy to see with the naked eye.

M42 is the Orion nebula. Itís visible to the naked eye, but binoculars will reveal a nice fuzzy patch, and a small telescope will reveal one of the most rewarding deep-space objects in the list.

The most distant object visible to the unaided eye is M31 Ė the Andromeda galaxy. It should be visible in the western sky as soon as it is dark enough. If you are attempting a Messier Marathon, there are two less prominent companions that are likely in the same field of view of a small telescope. M32 is a very small companion galaxy to M31. At low magnification, M32 might be mistaken for a nearby star if you donít notice the slight fuzziness.

Also in the field of view with M31 is M110, another companion that has a very low surface brightness. It is easier to notice such objects through the eyepiece if you use ďaverted vision.Ē In other words, donít look directly at the place you think it is, but look slightly off to the side. By moving your gaze around in the eyepiece, you can catch a glimpse of much fainter things than by looking directly at them.

If you havenít seen it yet, the comet PANSTARRS might be another candidate for averted vision viewing. It should still be visible in the western sky. Even if the nucleus of the comet is directly visible, it is possible that more of the tail will become visible with averted vision.

hakes_c@fortlewis.edu Charles Hakes is an assistant professor in the physics and engineering department at Fort Lewis College and is director of the Fort Lewis Observatory.